Ensure you have update server running and listening.
If the error still occurs, ensure that Assessment Writer is configured to communicate on the correct port and IP address. In Assessment Writer click FILE -> OPTIONS -> UPDATE and amend the server port number and/or IP address if necessary. Check with the School Technician or Report Coordinator if you are unsure of this setting.
If the Update Server is running and listening, check that the computer with assessment writer is able to ping the server computer. If the computer with Assessment Writer is able to ping the server, check the computer's firewall settings.